he decision by officials of the Diocese of San Bernardino, Calif., to file a claim against the Boston Archdiocese for failing to warn about an allegedly abusive priest appears to be the first case of its kind in the American church, but some legal specialists doubt it will be the last.

San Bernardino made the claim Tuesday in a case in which the diocese was named as a codefendant, with the Boston Archdiocese, in a suit filed by an alleged victim of the Rev. Paul R. Shanley -- a Boston priest who had moved into the California diocese.

The California diocese wants to be indemnified by Boston for any damages caused by Shanley, saying Boston knew and should have warned of Shanley's alleged abuse. It is a novel strategy, according to legal specialists following the abuse cases.

''I'm not aware of any cases where any diocese has sued another diocese in another clergy abuse case,'' said Patrick Schiltz, associate dean of the University of St. Thomas School of Law and a lawyer who used to represent Catholic dioceses. Carmen Durso, the Boston lawyer who represents Kevin English of Big Bear Lake, Calif., the alleged victim in the San Bernardino case, agreed that he had never heard of one diocese suing another as a result of abuse allegations.

Schiltz, however, said he doesn't think it will be the last such effort as abuse litigation mushrooms across the country.

''The bishop of San Bernardino has a duty to the people of San Bernardino to shift the burden to the other diocese,'' said Schiltz, adding that the San Bernardino bishop, facing large monetary damages if the verdict goes against the church, might believe the only alternative to closing church schools or agencies, or selling church properties, is suing the Boston Archdiocese.

Schiltz speculated that there could also be a public relations rationale behind the suit. ''It's a rather dramatic way to remind the public that the good dioceses were victimized by the bad dioceses,'' he said.

The Rev. Thomas J. Reese, editor of the Catholic weekly magazine America, suggested that the litigation may also stem from the fact that San Bernardino is a particularly poor parish, and thus unable to deal with costly lawsuits.

San Bernardino argued in its papers that Boston church officials knew of ''a long history of complaints'' against Shanley and ''numerous acts of serious misconduct'' by him.

But the record of what Boston church officials knew about Shanley's alleged misdeeds may not be that clear. Shanley worked part-time at St. Anne's parish in San Bernardino for three years after being transferred there from Massachusetts in 1990.

There is substantial documentary evidence that, at the time of his transfer, Boston church leaders knew Shanley had spoken favorably about sexual relations between men and boys, but it was not clear whether they also knew about child abuse accusations. Although one allegation had been made against Shanley as far back as 1966, Cardinal Bernard F. Law denied last year that he was aware of that accusation when Shanley went to California.

The California archdiocese maintains Boston is to blame for withholding information about Shanley at the time of his 1990 transfer. ''We have no responsibility in the actions that caused this lawsuit, so we don't believe our parishioners should have to bear this burden,'' said the Rev. Howard Lincoln, spokesman for San Bernardino Bishop Gerald R. Barnes.

Archdiocese lawyer Wilfrid C. Lemann added that the church's insurer urged San Bernardino to file against Boston. ''The insurance company was more than anxious for us to bring in other parties if they were responsible,'' said Lemann.

The Rev. Christopher J. Coyne, a spokesman for the Boston Archdiocese, said the church's lawyers had not yet seen the legal papers and could not respond.